The present invention relates to the field of analysis and quality control of transporting processes, in which consignments are handled and transported and in which parts of the handling operation, in particular sorting processes, are carried out mechanically.
A predominant field of use of the invention is the analysis and quality control of letter conveying and handling processes by means of objective measurement data obtained directly in the process.
The invention relates, in the narrower sense, to so-called electronic letters, that is to say consignments with electronic components and with conventional letter formats capable of being handled mechanically. Such apparatuses are capable of recording the physical quantities, such as, for example, acceleration, temperature, electric and magnetic fields, which act on them in their vicinity, of converting said quantities into electronic signals, and of processing these signals and storing them as data and do not require any modifications of or additions to the technical equipment involved in the transport process and also do not influence the latter.
The evaluation of the data recorded from electronic letters makes it possible to analyze the time profile of the transport of the electronic letter in the letter conveying and handling process. Consequently, precise conclusions as to whether regulations, rules and operating parameters are being adhered to in the various steps of the letter conveying and handling process can be drawn and weak points found and analyzed, and, therefore, if there are sufficiently large random samples, accurate data on the letter conveying and handling process can be obtained. Letter handling machines are designed and set in such a way that they handle an enormous number of letters with a high output and with a high degree of reliability and effectiveness. The letters capable of being handled in this way are designated, here, as normal letters. They are defined by the following features:
The length and width dimensions correspond to those of standardized letter formats or letter formats permitted by the national Mail Administrations or private mail services. PA1 The thickness of the normal letter is often in the range up to 2 mm. Letters with a thickness of 5 to 6 mm are permitted for mechanical handling. PA1 The thickness profile is constant over the entire normal letter and decreases only in the edge regions. PA1 The mass of the normal letter is usually lower than 20 g. However, because of the formats and letter thickness which can be used, masses of 50 to 60 g are possible and are permitted for machine handling. PA1 The density of the normal letter is uniform over the area. PA1 The resilience of the letter surface is low since the letter usually contains paper. PA1 Flexibility/pliability is uniform, anisotropic and high. PA1 The area center of gravity and mass center of gravity of normal letters are identical. PA1 Normal letters do not undergo plastic deformation during mechanical handling. PA1 Depending on the machine design, it is unimportant, for the normal letter, whether it is conveyed in a main or a secondary conveying direction. PA1 In this case, the main conveying direction runs along the long edges of the letter format and the secondary conveying direction runs along its short edges. PA1 Codes applied by letter handling machines by means of different printing methods (for example, ink jet, thermal transfer) for the coding of routes are machine-readable. PA1 In the preceding manual handling steps (preculling), normal letters are not sorted out by the personnel operating the apparatus on the basis of the visual and tactile impression which they give. PA1 are separated out in format separating and setting-up machines on account of too great a thickness and/or rigidity PA1 lead to jams in the letter run or at deflectors or at singling-out devices or leave the conveying stage in an uncontrolled manner PA1 lead to faults during stacking in stackers or compartments PA1 have stamp imprints of impaired readability PA1 have code imprints of impaired machine-readability PA1 necessitate manual corrections of the stack in intermediate stackers PA1 lead to increased wear of or damage to parts of the machines. PA1 belt pulling forces, jolt, shock and impact forces in the letter run in the main conveying direction PA1 belt pulling forces, jolt, shock and impact forces in the letter run in the secondary conveying direction PA1 bending forces at deflecting rollers and deflectors PA1 accelerations during drawing off and singling out PA1 braking accelerations during stacking in compartments, stackers or intermediate stackers PA1 compressive forces during stamping.
An essential criterion for the technical evaluation of letters is machine compatability. Normal letters are machine-compatible.
In addition to normal letters, letters are permitted for machine handling which, in one or more instances, reach limiting ranges regarding their physical properties (for example, letter thickness, rigidity/pliability, mass center of gravity, mass), so that they are machine-compatible to only a qualified extent, that is to say their machine compatibility is impaired. The result of this is that they are taken out more often than normal letters or part functions of the machines are disrupted or not properly executed more often or lead to greater wear of particular parts of the machine. Moreover, the machine compatibility of such letters depends particularly on the setting and the state of maintenance of the machines.
This qualified machine compatibility is present, in particular, when letters in widespread letter handling machines, more often than normal letters,
Furthermore, there are letters and other consignments which are always separated out manually before or mechanically at the start of handling (for example, in the format separating and setting-up region) on account of their physical properties, for example dimensions, letter thickness, thickness profile, rigidity/pliability, mass center of gravity, mass.
A further essential criterion for the technical evaluation of letters, which applies particularly to electronic letters which are machine-compatible, is machine resistance. This states to what extent and how often letters are damaged or destroyed during handling by the machine. In the case of normal letters, it is very rare that they are, for example, torn, ripped up or crumpled.
As regards electronic letters, it is obvious, by virtue of their makeup, that, if they do not have a stress-compliant design, it is possible more often that their functioning will be disrupted, they will be damaged, their service life may be reduced or they may be destroyed.
The following have a particularly adverse effect on the machine resistance of electronic letters:
So that the abovedescribed use of electronic letters is not subjected to any restrictions, they must be capable, without exception, of running through all the part-processes, without being separated out from individual process steps, without their functioning being disrupted or without them even being destroyed. Separating out in individual process steps would lead to a kind of further handling which is no longer representative of the process to be investigated. The reliability of data recorded in this way and of the quality characteristics derived from them would be restricted and, consequently, their value for assessing the quality of the letter conveying and handling process would be diminished.
DE-A 42 38 102 has already disclosed an apparatus for determining running times of letters, in which approximately 3/4 of the entire area of the electronic letter consists of two rigid printed card parts which are arranged in such a way that the circuit and the power supply are exposed, relatively unprotected, to all the mechanical effects of machine handling and may easily be destroyed. The flexible parts extend over the entire width of the printed card parts. Due to the high mechanical demands during mechanical handling and stamping and because it does not have the necessary machine compatibility, in the same way as normal letters, this apparatus does not possess any processing reliability over a relatively long period of time.
The object of the invention is to provide an apparatus which behaves in the same way as a normal paper letter in all the process steps of letter conveyance and handling and which can be handled by all conventional letter handling machines and thus makes it possible to ensure that the data obtained in the letter conveying and handling process are reliable and to increase functional reliability and service life.